package NC108_最大正方形;

import java.util.*;


public class Solution {
    /**
     * 最大正方形
     * @param matrix char字符型二维数组
     * @return int整型
     */
    public int solve (char[][] matrix) {
        // write code here
        int maxSide = 0;
        if (matrix == null || matrix.length == 0 || matrix[0].length == 0){
            return maxSide;
        }
        int row = matrix.length;
        int col = matrix[0].length;
        int[][] dp = new int[row][col];
        for (int i = 0; i < row; i++){
            for (int j = 0; j < col; j++){
                if (matrix[i][j] == '1'){
                    if (i == 0 || j == 0){
                        // dp数组初始数据
                        dp[i][j] = 1;
                    }else {
                        // 转移方程
                        dp[i][j] = Math.min(dp[i - 1][j - 1], Math.min(dp[i][i - 1], dp[i - 1][j])) + 1;
                    }
                    maxSide = Math.max(maxSide, dp[i][j]);
                }
            }
        }
        return maxSide * maxSide;
    }
}